Section 6 Study Guide

Question 1

A substance that undergoes a change in a chemical reaction is a __.

Answer 1

reactant

Question 2

In an exothermic reaction, energy is transferred from the ___ to the ___.

Answer 2

reactants; surroundings

Question 3

The energy source in photosynthesis is __

Answer 3

light energy

Question 4

A synthesis reaction is a reaction between at last two compounds in which __

Answer 4

a new, more complex compound is formed

Question 5

The product of the synthesis reaction between sodium and chlorine is __

Answer 5

sodium chloride

Question 6

A chemical equation is balanced by changing or adding

Answer 6

coefficients

Question 7

In a balanced chemical reaction, the total mass of the products always equals the __

Answer 7

total mass of the reactants

Question 8

Large, bulky molecules react more slowly than small ones because they have less opportunity to __

Answer 8

collide with other molecules

Question 9

Which enzyme breaks down cellulose into smaller molecules?

Answer 9

cellulase

Question 10

When a chemical reaction and its reverse are occurring at the same time and at the same rate, the reaction has achieved __

Answer 10

equilibrium

Question 11

Le Chatelier’s principle states that increasing temperature favors a reaction that __

Answer 11

absorbs energy as heat

Question 12

The changes that are visible during a chemical reaction are signs that the __ in the reactants have been rearranged

Answer 12

atoms

Question 13

A chemical reaction that transfers energy from the reactants to the surroundings is referred to as ___

Answer 13

exothermic

Question 14

In a __ reaction, the reactants are broken down into other substances

Answer 14

decompostion

Question 15

A substance is said to be __ when it gains electrons

Answer 15

reduced

Question 16

When a reaction is at equilibrium, increasing the pressure favors the reaction that produces __

Answer 16

less gas

Question 17

In a state of equilibrium, a reaction and its reverse occur at the same __ and at the same __

Answer 17

time; rate

Question 18

What is true about endothermic reactions?

Answer 18

Heat is transferred from the surroundings to the reactants.

Question 19

Most of the energy in an isooctane reaction is released in the form of __

Answer 19

heat and light

Question 20

What is an example of a decomposition reaction?

Answer 20

digestion

Question 21

When water is broken down by electrolysis, the products are __

Answer 21

hydrogen gas and oxygen gas

Question 22

A balanced chemical equation shows the proportions of reactants and products necessary for __

Answer 22

mass to be conserved

Question 23

An enzyme is a special kind of catalyst that works to __

Answer 23

speed up a specific biochemical reaction

Question 24

What is the relationship between chemical equilibrium and the rates forward and reverse reaction?

Answer 24

the forward and reverse reactions must be equal

Question 25

Increasing the concentration of one substance in an equilibrium reaction favors the reaction that ___

Answer 25

produces less of that substance

Question 26

A sign that a chemical reaction is taking place is release of energy in the form of __ or __

Answer 26

light; heat

Question 27

An __ reaction is one in which heat is transferred from the surroundings to the reactants

Answer 27

endothermic

Question 28

In a combustion reaction, __ is used to make reactants burn

Answer 28

oxygen

Question 29

A reaction that involves the transfer of electrons is called a ___ or _____ reaction

Answer 29

redox; reduction/oxidation

Question 30

Equilibrium is achieved when the __ and __ reactions continue to take place at the same rate

Answer 30

forward; backward

Question 31

When a reaction is at equilibrium, increasing the temperature favors the reaction that __

Answer 31

absorbs energy as heat